In a case in which a plurality of elevators are installed in a building, an elevator group control apparatus is disposed to employ the plurality of elevators efficiently to reduce the passenger waiting time.
The elevator group control apparatus is aimed at reducing the passenger waiting time, and also achieving energy conservation.
For example, an elevator group control apparatus disclosed by patent reference 1 which will be mentioned below is so constructed as to set up a receivable number of hall calls for each floor, and, when the number of hall calls which have occurred at each floor exceeds the receivable number of hall calls, not to receive any newly-occurring hall call. Thereby, the utilization of the plurality of elevators is restricted and energy conservation can be achieved.
However, at a floor at which the number of hall calls which have occurred exceeds the receivable number of hall calls, the passengers at the floor cannot board any one of the elevators and a very inconvenient status occurs.
In contrast, when the number of hall calls which have occurred is less than the receivable number of hall calls, no energy conservation is achieved because the utilization of the plurality of elevators is not restricted.
An elevator group control apparatus disclosed by patent references 2 which will be mentioned below, in a case of carrying out standby control when there are few passengers, estimates the probability of occurrence of hall calls at each floor.
Then, when there are a plurality of floors at each of which its probability of occurrence of hall calls falls within a predetermined range, the elevator group control apparatus selects, as a waiting floor, a floor which is close to a left elevator from among the plurality of floors at each of which its probability of occurrence of hall calls falls within the predetermined range, and makes an elevator be on standby at the waiting floor. As a result, compared with a case in which a fixed floor is made to be the waiting floor, the distance over which an elevator is made to travel to the waiting floor can be reduced, and therefore energy conservation can be achieved.
However, in this case, energy conservation is restrictly achieved only during off-peak times when the number of passengers is small with a little movement of each elevator, and the running distance over which an elevator is made to travel toward the waiting floor is not so long. Therefore, the energy conservation effect is restricted.    [Patent reference 1] JP,2002-167129,A (see the paragraph numbers [0017] to [0021] and FIG. 1)    [Patent reference 2] JP,10-36019,A (see the paragraph number and FIG. 2)
Because conventional elevator group control apparatuses are constructed as mentioned above, when the number of hall calls which have occurred at each floor exceeds the receivable number of hall calls, if a measure of not receiving any newly-occurring hall call is taken against this event, the utilization of the plurality of elevators is restricted and energy conservation is achieved. However, at a floor at which the number of hall calls which have occurred exceeds the receivable number of hall calls, the passengers at the floor cannot board any elevator and a very inconvenient status occurs. A further problem is that, when the number of hall calls which have occurred is less than the receivable number of hall calls, no energy conservation is achieved because the utilization of the plurality of elevators is not restricted.
Furthermore, in a case in which a floor at which the probability of occurrence of hall calls falls within a predetermined range is made to be a waiting floor, compared with a case in which a fixed floor is made to be the waiting floor, the distance over which an elevator is made to travel to the waiting floor can be reduced, and therefore energy conservation can be achieved. Another problem is, however, that because, while energy conservation is achieved, the energy conservation is restricted to during off-peak times when the number of passengers is small with a little movement of each elevator, and the running distance over which an elevator is made to travel toward the waiting floor is not so long, the energy conservation effect is restricted.
The present invention is made in order to solve the above-mentioned problems, and it is therefore an object of the present invention to provide an elevator group control apparatus which can reduce the travelling distance of each elevator without causing occurrence of an inconvenient status in which, for example, the passenger waiting time becomes long, thereby enhancing the energy conservation effect.